1. Field of the Invention
The present invention concerns an axle puller for removing an axle from a wheel assembly, and more particularly concerns an axle puller that applies an extraction force on each of the lug bolts of a wheel assembly.
2. Description of the Prior Art
The problems with removing an axle from a wheel assembly are well documented. The axle is typically an elongated shaft having an axle plate mounted perpendicularly to one end. The plate has a plurality of circumferentially spaced holes formed therein. The wheel assembly typically includes, in addition to the axle, a hub portion attached to an elongated tubular shaped axle housing. The hub and axle housing define an axial cylindrical cavity. When the axle is positioned in the wheel assembly, the shaft fits axially into the cylindrical cavity through the center of the hub and the axle housing. The axle plate butts up against the hub which has a plurality of lug bolts extending generally axially outwardly therefrom and through the holes in the axle plate. Often times conical washers are used between the lug bolts and the axle plate to facilitate a tight connection of the axle plate to the hub. Standard nuts are used on the lug bolts to tighten the axle plate against the hub.
During use, the axle plate and lug bolts are exposed to weather elements, and also to severe stresses caused by acceleration and braking. The exposure to weather can cause the lug bolts to rust in place in the axle plate, or can cause the conical washers to become fixed within the holes and to the lug bolts because of rust. Also, the stresses experienced by the wheel housing and axle combination during use can cause the lug bolts or conical washers to become deformed. In any case, the axle becomes "frozen" to the wheel assembly and is difficult to remove therefrom.
A common technique of removing the axle from the wheel assembly is to percussively impact the end of the axle after the lug nuts have been removed. A sledge hammer is often used to impact the end of the axle, resulting in loosening the axle from within the wheel assembly. The impact can also severely damage the axle plate and the stud bolts. This impact also causes uneven stress to be placed on the different parts of the wheel assembly and axle, thus sometimes causing further damage to the axle or wheel assembly.
Several devices have been developed in order to address the problems associated with removing an axle from an wheel assembly. U.S. Pat. No. 1,865,420 issued to Kick describes a hub puller for pulling a hub off an axle using a flanged structure to grip the wheel while applying a retraction force by tightening a pair of laterally opposed bolts. Hammer blows to an end piece are used to jar the hub off the axle.
U.S. Pat. No. 3,025,595 issued to Stafford describes an axle puller that fits between the axle plate and the hub. The axle puller has threaded portions which, upon turning, extract the axle from the hub.
U.S. Pat. No. 1,601,752 issued to Wortham describes a pulling apparatus utilizing a pair of grip arms to secure the body to be pulled, and also has a center shaft which upon turning applies a force to the centerpiece and subsequently extracts the body from the centerpiece.
U.S. Pat. No. 1,599,738 issued to Atkins describes a bushing puller which utilizes grip arms to engage the bushing, and also leveling screws to ensure the bushing is being retracted in the proper orientation. The grip arms are held in position by a gear tooth engagement with a central shaft. The central shaft is threaded, and thus when rotated applies a force to the bushing shaft to extract the bushing.
U.S. Pat. No. 4,965,921 issued to Priest describes an axle puller with an elongated main body with two arms adjustably extending from both ends of the main body. The distal end of each of the arms has a wide portion which engages a back side of the axle flange. The arms adjust to cause the main body of the axle puller to engage two diametrically opposed lug bolts mounted on the hub. The engagement of the main body with the lug bolts biases the axle plate towards the main body and away from the wheel assembly. A center shaft runs through a bore at the center of the main body for use in striking the end of the axle to cause an impact and jar the axle loose from the hub.
The prior art does not describe an axle puller which remains easily mounted on the hub during application of the axle puller, and also applies an even extraction force on each of the lug bolts to help ensure complete separation of the axle from the wheel assembly without causing any damage to the axle or hub during removal. The "frozen" connection between the axle and the hub caused by physical deformation or exposure to weather elements could be strong enough that the use of prior art tools to remove the axle could damage the axle, wheel assembly, or the tool itself.